Donut Tutorial Coffee Cup has holes in it
The first thing I noticed is that you just have some extra geometry in there that you definitely don't need. You can select contiguous bits of mesh by hovering over them with the cursor and hitting L. Delete the excess:



Next you need to delete the interior faces of the handle. I've temporarily disabled the subdivision modifier here so I can better see what I'm doing:



In face select mode, I first hold down ALT (to select loop) and click to select one face loop, then SHIFT + ALT (to select loop and keep previous selection) to select the other, and delete these faces. 

I used L to select the now disconnected geometry that comprised the inside of the handle, and deleted that too.

In Edge select mode, I hold SHIFT + ALT to select the edge loops surrounding the now open holes in the mesh, and press F to fill them. The last step is removing the creases and reenabling the subdivision surface.